In Cleeves’s exquisitely plotted sixth Shetland mystery (after 2013’s Dead Water), bridesmaid Eleanor Longstaff disappears during a wedding ceremony on the island. When she turns up dead in a shallow loch, Det. Insp. Willow Reeves and colleague Jimmy Perez investigate. The pair have difficulty establishing a motive for murder in the close-knit local community and among the university friends who make up the wedding party, but they soon discover that Eleanor was researching a ghost story for a TV show about Elizabeth Geldard, a young girl who died nearly a hundred years earlier but has been repeatedly spotted dancing on an island beach, in a white dress and ribbons. It becomes increasingly likely that Eleanor’s research led to her demise, and if Willow and Jimmy don’t find the killer, her death may not be the only one. Cleeves deftly explores the complicated personal relationships of the principal characters in this atmospheric installment. Agent: Sarah Menguc, Sarah Menguc Literary Agent (U.K.). (May)